Abstract

Introduction

The coexistence of autoimmune hyperthyroid disease and thyroid-stimulating hormone-secreting
pituitary adenoma is rare. The simple presumption of coincidence of these two diseases
has a calculated incidence of less than one/several hundred million, and only four
cases with histological confirmation have been reported. A rapid decrease in thyroid-stimulating
hormone level after pituitary tumor removal may induce subsequent activation of autoimmune
responses against the thyroid gland. We report the first case of a sequential and
paradoxical occurrence of Graves’ disease and a thyroid-stimulating hormone-secreting
pituitary adenoma.

Case presentation

A 32-year-old Japanese woman had recurrent hyperthyroidism. She had a history of Graves’
hyperthyroidism, which had been successfully treated with propylthiouracil. A head
magnetic resonance imaging showed a less enhanced area in the left lateral wing of
her sella turcica. Transsphenoidal surgery was performed, and the diagnosis was established
as thyroid-stimulating hormone-secreting plurihormonal adenoma. A rapid reduction
in thyroid hormone levels was achieved, and her blood pressure was normalized after
the operation.

Conclusion

Although incidental occurrence is the most probable etiology, long and repeated followup
examinations of both thyroid and pituitary gland should be performed in patients with
an atypical clinical course.